SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '728ae8293a4c706cc4886231b8322eea960b6c956f918c7c80490d0d26b26ee4' 
  AND token = 'KKnuugI5Z2KSj6iYePX3IwgNLA2sZ7UKx/kgvFapHR8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}